聚酰亚胺的化学结构在炭膜制备过程中的变化规律及热解机理

李琳; 祁文博; 王虹; 张萍萍; 孙美悦; 王同华; 李建新; 曹义鸣

聚酰亚胺的化学结构在炭膜制备过程中的变化规律及热解机理

1.
大连理工大学精细化工国家重点实验室炭素研究室, 辽宁大连 116023;
2.
天津工业大学中空纤维膜材料与膜过程省部共建国家重点实验室培育基地, 天津 300023;
3.
中国科学院大连化学物理研究所, 辽宁大连 116001

基金项目: 国家自然科学基金(20976021,21176036);国家高技术研究发展计划(863, Z2012AA03A611);中国博士后第56批科学基金(2014M561232);中央高校基本科研业务费专项(DUT14RC(3)119).

详细信息

作者简介:
李琳,讲师.E-mail:lilin121@dlut.edu.cn

通讯作者:
王同华,教授.E-mail:wangth@dlut.edu.cn

中图分类号: TQ127.2
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出版历程
- 收稿日期: 2015-06-20
- 录用日期: 2015-11-10
- 修回日期: 2015-10-09
- 刊出日期: 2015-10-28

Pyrolysis of polyimide membranes from the same dianhydride monomer and different diamines to form carbon membranes

1.
State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116023, China;
2.
Hollow Fiber Membrane Materials and Membrane Process Laboratory as the State Key Lab Incubation Base in China, Tianjin Polytechnic University, Tianjin 300023, China;
3.
Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116001, China

Funds: National Natural Science Foundation of China(20976021,21176036);National High Technology Research and Development(Z2012AA03A611);China Postdoctora/Science Foundation(2014M561232);Fundamental Re-search Funds for the Central Universities(DUT14RC(3)119).

摘要

摘要: 从分子设计出发,用不同的二胺单体和相同的二酐单体合成聚酰胺酸并制备聚合物膜。采用热重、热重-质谱、红外和X射线光电子能谱分析聚酰胺酸在热解过程中的结构变化及机理。结果表明,在热解过程中,聚酰胺酸的热解包括4个阶段,经吸附水和吸附氧的脱除及溶剂挥发,亚胺化,交联,以及高温阶段的主链断裂、脱氧、脱氢、芳构化等热解过程转化为无定形炭结构。前驱体的结构不同导致热解过程存在差异。PPD-PMDA和TMPPD-PMDA热解时所需的温度较高。其它聚酰亚胺析出CH₄、CO₂、C₆H₆的温度顺序为ODA-PMDA >BDAF-PMDA >BAPP-PMDA。在700℃热解后,BDAF-PMDA所含的氟元素基本消失。这表明聚酰亚胺的化学结构对炭膜的微结构有较大影响。
- 聚酰亚胺 /
- 炭膜 /
- 化学结构 /
- 热解机理
Abstract: Polyimide membranes were synthesized by the polymerization of five diamines, p-phenylenediamine (PPD), 2,3,5,6-tetramethyl-1,4-phenylenediamine (TMPPD), 4,4'-oxydianiline (ODA), 4,4'-(4,4'-isopropylidenediphenyl-1,1'-diyldioxy)dianiline (BAPP) and 4,4'-(hexafluoroisopropylidene)bis(p-phenyleneoxy) dianiline (BDAF), and the same dianhydride monomer, 1,2,4,5-benzenetetracarboxylic anhydride (PMDA). The chemical structures of the membranes pyrolyzed at different temperatures were investigated by TGA, TG-MS, FT-IR and XPS. Results indicate that there are five stages during pyrolysis: (a) the removal of the solvents, adsorbed oxygen and water, (b) imidization, (c) cross-linking and carbonization, which are accompanied by main chain breaking, (d) deoxygenation and dehydrogenation, (e) aromatization and turbostratic carbon formation. The chemical structure of the precursor is the main factor that causes the great differences in chemical structures during pyrolysis. Imidization in the pyrolysis of the PPD-PMDA and TMPPD-PMDA occurs at higher temperatures than those for ODA-PMDA, BDAF-PMDA and BAPP-PMDA. The order of temperatures for the release of CH₄, CO₂ and C₆H₆ during the pyrolysis is ODA-PMDA >BDAF-PMDA >BAPP-PMDA. Elemental F in the BDAF-PMDA disappears after pyrolysis at 700℃. The chemical structures of the polyimides have a great influence on the microstructures of the carbon membranes obtained.
- Polyimide /
- Carbon membrane /
- Chemical structure /
- Pyrolysis mechanism

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